A discrepancy in the magnitude of thujone concentrations in distilled pre-ban absinthe has existed until now. Concentrations of 260 mg L-1 were derived at by theoretical calculations. Tests of authentic pre-ban absinthes and studies concerning absinthes produced according to historic recipes found concentrations below 10 mg L-1. In this study, the behaviour of thujone during distillation was studied and a significant discrimination was determined (80% yield in water-cum-steam distillation). The thujone concentrations in distilled pre-ban absinthe were then calculated with regard to the composition of wormwood derived from a literature review. Due to the large deviations of oil content and thujone concentration of wormwood, a typical Absinthe Suisse de Pontarlier from Duplais' 1855 recipe might have contained between zero and a maximum of 76 mg L-1 of thujone, the average was calculated as 23 mg L-1 with a standard deviation of 21 mg L-1. It was proven that the previous calculations overestimated the thujone content of distilled absinthe and the discrepancy was resolved as our new calculations are in good accord with the experimental findings.